_compute_abi_rebuild_info: deal with non-Package parents
diff --git a/pym/_emerge/depgraph.py b/pym/_emerge/depgraph.py
index f27e855..abb70a7 100644
--- a/pym/_emerge/depgraph.py
+++ b/pym/_emerge/depgraph.py
@@ -643,7 +643,7 @@
 			rebuild_atoms = atoms.get(root, set())
 
 			for dep in deps:
-				if dep.parent.installed or dep.child.installed or \
+				if getattr(dep.parent, "installed", False) or dep.child.installed or \
 					dep.parent.slot_atom not in rebuild_atoms:
 					continue